Bilateral Hip BMD Should be Me
By
Medscape Medical News
Pippa Wysong
Sept. 24, 2003 (Minneapolis) — When assessing bone mineral density (BMD) of the hip in older women, measurements should be done for both sides, not just one.
That is the recommendation of a researcher who found that there are significant differences between the hips of up to 20% of older women, with many having normal values on one side and osteoporosis on the other.
"In women who are over 60 years of age and who are heavier, more than 71 kg, two measurements are better," said Jose Luis Mansur, MD, director of the Center for Endocrinology and Osteoporosis in La Plata, Argentina.
In a study investigating bilateral hip BMD, it was found that significant differences between the left and right hip appeared in women who did not have scoliosis or other conditions that could indicate there might be differences. Findings were presented here at the 25th annual meeting of the American Society for Bone and Mineral Research.
BMD was measured in 100 postmenopausal women (mean age, 60 years). Hips were rated as normal, as having osteopenia, or as having osteoporosis. Women with scoliosis and those who had previous treatment with drugs that affect bone metabolism were excluded.
In measurements of the femoral neck, 81% of the women had concordance between both sides. Of the 19% that were discordant, 14% were rated as being either normal or as having osteopenia, and 5% of the hips had osteoporosis.
In measuring total hip BMD, there was 84% concordance. Of the 16% that were discordant, 11% were normal or had osteopenia while 5% had osteoporosis.
Of the 100 women, a total of 40 were older than 60 years, with discordance occurring in 32.5% of the femoral neck measurements and in 17.5% of the total hip measurements. Heavier weight played a role too, increasing the likelihood of discordance, Dr. Mansur said.
"Although the correlation between both hips is high, a significant number of patients without scoliosis have a difference between sides, and nearly 20% are classified in different way if we choose only one side," Dr. Mansur said.
The classification differences could affect treatment decisions. He suggested that older, heavier patients have BMD measured on both sides.
The results are not surprising, said Marian Hannan, DSc, assistant professor of medicine and aging at Harvard Medical School in Boston, Massachusetts. She was not involved in the study.
In large studies such as the Framingham study, epidemiologists tend to want to measure only one side when coming up with values for populations. When large numbers are averaged out, it appears that there is concordance.
But "if you're going to use it for treatment, you may want to take both hips," Dr. Hannan said, because it is more meaningful for an individual patient. Some nursing home data suggest that there can be differences in hip BMD depending on whether a person is left- or right-handed, and how mobile an individual is on either side.
On the other hand, she said, measurements are often done at additional sites, which could make up for not measuring both hips.
Dr. Mansur received no outside funding for this study.
25th ASBMR: Abstract M087. Presented Sept. 22, 2003.
Reviewed by Gary D. Vogin, MD
Pippa Wysong is a freelance writer for Medscape.
